Pandas 中 iloc 的奇怪错误：IndexError: single positional indexer is out-of-bounds

Question

我正在使用 Pandas 和 Flask 开展一个项目，但遇到了以下奇怪的错误：IndexError: single positional indexer is out-of-bounds。然而，错误本身并不奇怪，奇怪的是它是如何发生的。我有一个烧瓶应用程序，其中一个页面是进行 ajax 调用的表单。用户输入书名并返回该书的平均评分。如果我输入“它”，那么评分就会返回。一切正常。但是，如果我输入火车上的女孩，我会收到以下错误：

Traceback (most recent call last):
  File "/Library/Frameworks/Python.framework/Versions/3.4/lib/python3.4/site-packages/flask/app.py", line 1994, in __call__
    return self.wsgi_app(environ, start_response)
  File "/Library/Frameworks/Python.framework/Versions/3.4/lib/python3.4/site-packages/flask/app.py", line 1985, in wsgi_app
    response = self.handle_exception(e)
  File "/Library/Frameworks/Python.framework/Versions/3.4/lib/python3.4/site-packages/flask/app.py", line 1540, in handle_exception
    reraise(exc_type, exc_value, tb)
  File "/Library/Frameworks/Python.framework/Versions/3.4/lib/python3.4/site-packages/flask/_compat.py", line 33, in reraise
    raise value
  File "/Library/Frameworks/Python.framework/Versions/3.4/lib/python3.4/site-packages/flask/app.py", line 1982, in wsgi_app
    response = self.full_dispatch_request()
  File "/Library/Frameworks/Python.framework/Versions/3.4/lib/python3.4/site-packages/flask/app.py", line 1614, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "/Library/Frameworks/Python.framework/Versions/3.4/lib/python3.4/site-packages/flask/app.py", line 1517, in handle_user_exception
    reraise(exc_type, exc_value, tb)
  File "/Library/Frameworks/Python.framework/Versions/3.4/lib/python3.4/site-packages/flask/_compat.py", line 33, in reraise
    raise value
  File "/Library/Frameworks/Python.framework/Versions/3.4/lib/python3.4/site-packages/flask/app.py", line 1612, in full_dispatch_request
    rv = self.dispatch_request()
  File "/Library/Frameworks/Python.framework/Versions/3.4/lib/python3.4/site-packages/flask/app.py", line 1598, in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File "/Users/mikecuddy/Desktop/Coding/Python/book_ratings/app.py", line 75, in book_look_up
    rating = book.book_rating(title)
  File "/Users/mikecuddy/Desktop/Coding/Python/book_ratings/books.py", line 17, in book_rating
    rating = info.iloc[0][12]
  File "/Library/Frameworks/Python.framework/Versions/3.4/lib/python3.4/site-packages/pandas/core/indexing.py", line 1296, in __getitem__
    return self._getitem_axis(key, axis=0)
  File "/Library/Frameworks/Python.framework/Versions/3.4/lib/python3.4/site-packages/pandas/core/indexing.py", line 1612, in _getitem_axis
    self._is_valid_integer(key, axis)
  File "/Library/Frameworks/Python.framework/Versions/3.4/lib/python3.4/site-packages/pandas/core/indexing.py", line 1526, in _is_valid_integer
    raise IndexError("single positional indexer is out-of-bounds")
IndexError: single positional indexer is out-of-bounds

但是，如果我在我的 pandas 代码中输入相同的标题，我会得到评分！我知道我的 Pandas 代码运行良好。我还要说，任何书名只有一个单词，例如它，都可以正常工作。只有标题中有多个单词才会出现我的错误。我已经将问题追溯到此，但无法进一步解决。现在我的代码：

HTML 代码

<form class='title_lookUp_div' id='book_look_up_form'>
    <label>Book Title: </label><input id='title' name='title' type='text'>
    <p>Result: <span id='result'>?</span></p>
    <button>Submit</button>
</form>

JS/AJAX 调用：

$(document).ready(function(){
  $('#book_look_up_form').bind('submit', function(event){
    event.preventDefault();
      $.ajax({
        data: {
          title: $('#title').val()
        },
       type: 'POST',
       url: '/book_look_up',
       success: function(data){
       $('#result').text(data.result).show();
      }
    });
   });
  });

熊猫代码：

    def book_rating(self, title):
       #Gettting the row of data for the title that the user entered.
       info = self.__data[self.__data.original_title == title]
       rating = info.iloc[0][12]
       return rating

app.py 代码：

@app.route('/book_look_up',methods=['POST'])
def book_look_up():
   #Recieving the data from the ajax call
   title = request.form['title']
   #The data in the CSV file has the first letter of each word capitalized 
   title = title.title()
   #Creating the object that will deal with the data from CSV file.
   book = Books()
   rating = book.book_rating(title)
   if title: 
      return jsonify(result = rating)
   return jsonify({'error' : 'Missing Data'})

就像我说的，Pandas 代码运行良好，app.py 和 ajax 调用运行良好。只是当数据中有多个单词时，一切都崩溃了，我得到了错误消息。任何帮助都会很棒！谢谢！

Answer 1

经过多次审查，事实证明这是一个正则表达式问题。请看我上面的cmets。在此示例中，我的问题来自 .title() 方法，该方法更改了在 CSV 文件中搜索标题的方式。